To do this follow the below instructions

Login to website

Go to: Admin > Publishing > Folders

Select the article you wish create the hyperlink

Edit Article

Highlight the text that you wish to create the link

Click on Hyperlink Manager or press Ctrl+K

In the Hyperlink Tab

Enter the url e.g http://www.elcom.com.au

If you wish to open the link in a new window

Change the Target field to New Window

Once you have done that click on OK

Then Save & Check In article or click on Publish for CM Versions 5.8 and higher